I am not using GraphQL, just using iOS Sync. Where would I be able to change this?
I ran into the same issue today, do you have any update from the team?
I seems that the root cause is that no matter what the field type is, using a function to update it, it must have a value.
Non existent key, key set to null or key set to undefined does not work.
For my optional string schema, I had to pass an empty string ""